[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 4/8] ns16550: support DesignWare 8250
On Tue, 2013-09-10 at 16:02 +0100, Jan Beulich wrote: > >>> On 10.09.13 at 16:18, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote: > > @@ -233,6 +234,16 @@ static void ns16550_setup_preirq(struct ns16550 *uart) > > /* No interrupts. */ > > ns_write_reg(uart, UART_IER, 0); > > > > + if ( uart->dw_usr_bsy && > > + (ns_read_reg(uart, UART_IIR) & UART_IIR_BSY) == UART_IIR_BSY ) > > + { > > + /* DesignWare 8250 detects if LCR is written while the UART is > > + * busy and raises a "busy detect" interrupt. Read the UART > > + * Status Register to clear this state. > > + */ > > + (void)ns_read_reg(uart, UART_USR); > > Pointless cast? It's a hint to the compiler/reader that the return value is deliberately discarded. We have a handful of these in the tree already. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |